The present invention relates to a fungicidal composition comprising a fungicidally acceptable carrier and/or surface active agent and synergistically effective amounts of
(a) at least one azolopyrimidine of formula I ##STR2## PA0 in which PA0 x is the efficacy in % compared with an untreated control upon treatment with a fungicidal active ingredient A at a dose rate a; PA0 y is the efficacy in % compared with an untreated control upon treatment with a fungicidal active ingredient B at a dose rate b; PA0 EE is the expected efficacy with a combination of fungicidal active ingredients A and B at a dose of a+b, respectively. PA0 wherein PA0 in which PA0 wherein PA0 group of formula ##STR6## PA0 (i) a unit which comprises at least one azolopyrimidine of formula I, in particular one or more compounds selected from the Azolopyrimidines A, B or C, conventional carriers and optionally adjuvants; PA0 (ii) a unit which comprises at least one active ingredient selected from the classes (A), (B) and (C), preferably one or more compounds selected from the group consisting of carboxin, fluazinam, quinoxifen, metalaxyl, famoxadone, metconazole, epoxiconazole, propiconazole, azoxystrobin or kresoxim methyl conventional carriers and optionally adjuvants.
R.sup.1 represents a C.sub.1-6 alkyl, C.sub.3-6 alkenyl or C.sub.1-6 haloalkyl group, or PA1 R.sup.2 represents a hydrogen atom or a C.sub.1-6 alkyl group, or PA1 R.sup.1 and R.sup.2 taken together represent a C.sub.3-8 alkylene group, PA1 L.sup.1 represents a halogen atom; PA1 L.sup.2 and L.sup.3 each independently represent a hydrogen or a halogen atom; and PA1 and at least one fungicidal active ingredient selected from the following classes (A), (B) and (C): PA1 (A) a compound selected from the group consisting of benomyl, carboxin, captan, chlorothalonil, copper oxychloride, cyprodinil, dimethomorph, dithianon, dodine, famoxadone, fenpiclonil, fenpropimorph, fluazinam, mancozeb, metalaxyl, pyrimethanil, quinoxifen, sulfur, triforine and vinclozolin; PA1 (B) a fungicidal triazole derivative; and PA1 (C) a synthetic strobilurine derivative. PA1 L represents a linking group selected from the groups (a), (b), (c) and (d) ##STR4## PA1 X.sup.1 represents an alkyl or an optionally substituted phenyl group; PA1 X.sup.2 and X.sup.3 each independently represent a hydrogen atom or an alkyl group; PA1 X.sup.4 represents an alkyl or cyclopropylalkyl group; PA1 q is 1 or 2; and PA1 n is 0 or 2. PA1 A represents N or CH; PA1 B represents a --O--, --OCH.sub.2 --, a --CH.sub.2 O--, a pyrimid-4,6-dioxydiyl group or a PA1 R.sup.3 represents a C.sub.1-4 alkyl group; PA1 R.sup.4 represents a C.sub.1-6 alkoxy or a C.sub.1-6 alkylamino group; PA1 R.sup.5 represents a hydrogen or halogen atom or a cyano, a C.sub.1-4 alkyl or a C.sub.1-4 haloalkyl group; and PA1 m is 0, 1 or 2; PA1 a carrier agent; PA1 at least one azolopyrimidine of formula I, PA1 at least one compound selected from the classes (A), (B) and (C) as defined above; PA1 optionally an adjuvant selected from the group consisting of polyalkoxylated alcohols, triglycerides and amines, in particular Synperonic 91-6, which is commercially available from ICI Surfactants; PA1 optionally a foam breaking agent, in particular a mixture of perfluoroalkyphosphonic acids and/or perfluoroalkylphosphinic acids, in particular Defoamer SF or Fluowett PL, which are commercially available from Clariant GmbH.
(A) a compound selected from the group consisting of benomyl, carboxin, captan, chlorothalonil, copper oxychloride, cyprodinil, dimethomorph, dithianon, dodine, famoxadone, fenpiclonil, fenpropimorph, fluazinam, mancozeb, metalaxyl, pyrimethanil, quinoxifen, sulfur, triforine and vinclozolin; PA2 (B) a fungicidal triazole derivative; and PA2 (C) a synthetic strobilurine derivative.
The fungicidal compounds of formula I to be used according to the present invention are known from U.S. Pat. No. 5,593,996. The compounds of the classes (A) and (B) are known from "The Pesticide Manual", 11th edition (1997), Editor Clive Tomlin. Fenhexamid is known from AGROW No. 287, p. 21. The synthetic strobilurines are known, for example, from WO 92/08703, EP 0 253 213 and EP 0 398 692.
However, none of the above mentioned prior art references teaches a combination of compounds of formula I with any of the fungicidal active ingredients selected from the classes (A), (B) and (C) as described above, nor that such mixtures show synergistic effects and can advantageously be used for controlling diseases such as wheat powdery mildew, barley powdery mildew, wheat leaf rust, barley net blotch and wheat Septoria leaf blotch, Botrytis diseases and others.
Surprisingly, when compounds of formula I were tank mixed with compounds from classes (A), (B) and (C) and used in greenhouse and field trials, a synergistic increases in activity were observed, compared to the activity expected based on the activities of the individual active ingredients.
A mixture of fungicides shows synergistic effect if the fungicidal activity of the mixture is larger than the sum of activities of the separately applied compounds. The expected fungicidal activity for a given mixture of two fungicides can also be calculated as follows (See Colby, S. R., "Calculating synergistic and antagonistic response of herbicide combinations", Weeds 15, pp 20-22 (1967): EQU EE=x+y-x.multidot.y/100
wherein
If the actual efficacy (E) exceeds the expected (calculated) one (EE), the mixture displays a synergistic effect.